High speed magnetic thrust disk

ABSTRACT

The present invention contemplates an internally reinforced high-speed magnetic thrust disk. In one embodiment the internally reinforced composite thrust disk comprises a plurality of high strength fibers coupled together by a soft magnetic alloy. Further, in one aspect the disk having internally reinforced zones for controlling bore growth and counteracting forces associated with the reaction between the stator and the rotor of the electromagnetic thrust bearing system.

BACKGROUND OF THE INVENTION

The present invention relates generally to the design and fabrication ofa composite structure comprising soft magnetic alloys and high strengthfibers. More particularly, the present invention has one form defined byan internally reinforced metal matrix composite thrust disk for use inan electromagnetic thrust bearing. The selectively reinforced regions ofthe thrust disk contain a high strength iron cobalt metal matrixcomposite material. Although the present invention was developed for usein gas turbine engines, certain applications may be outside this field.

It is well known that a gas turbine engine integrates a compressor and aturbine having components that rotate at extremely high speeds in a hightemperature environment. One component is a rotor disk that carries aplurality of airfoils utilized to influence the gaseous flow within theengine. The rotating components typically cooperate with a rotatableshaft and are supported by radial bearings and a thrust bearing thatmust withstand significant dynamic and static loads within a hostileenvironment. During operation of the gas turbine engine, the bearingsare subjected to forces including: shock loads, such as from landings;maneuver loads, such as associated with sudden change in direction; and,centrifugal loads attendant with the mass of the rotating components.

The desire to increase efficiency and power output from gas turbineengines has caused many engine designers to consider the application ofmagnetic bearings for supporting the rotor and rotatable shaft. Theintegration of magnetic bearings into an engine will enable the rotorand rotatable shaft to be supported by magnetic forces, eliminatefrictional forces, eliminate mechanical wear and allow the removal ofthe lubrication system.

Magnetic thrust bearings include a magnetic flux field and a rotatablethrust disk that is acted upon by the magnetic flux field. Theapplication of magnetic thrust bearings in flight weight gas turbineengines require compactactness of bearing design, which ultimatelyequates to lighter weight. Prior designers of gas turbine engines haveutilized materials for the rotating thrust disk that experience a lossof mechanical properties at elevated temperatures. This loss ofmechanical properties limits the maximum rotational speed that thethrust disk can be operated at, thereby effectively limiting the maximumrotational speed of the engine.

Although the prior techniques utilizing magnetic thrust bearings for gasturbine engines are steps in the right direction, the need foradditional improvement still remains. The present invention satisfiesthis need in a novel and unobvious way.

SUMMARY OF THE INVENTION

One aspect of the present invention contemplates a high-speed internallyreinforced magnetically responsive thrust member.

In one form of the present invention there is contemplated an apparatus,comprising: a housing; a member rotatable relative to the housing; amagnetically responsive structure coupled to and rotatable with themember, the structure formed of a soft magnetic alloy material with atleast a portion of the structure internally reinforced with at least oneelongated high strength reinforcing member.

Another form of the present invention contemplates an electromagneticthrust bearing, comprising: a stator having a stator surface; a rotorhaving a rotor surface spaced from the stator surface, the rotor havinga first internally reinforced portion for inducing a first roll to therotor to cancel at least a portion of an opposite second roll induced inthe rotor by an attractive force between the rotor and the stator.

In yet another form of the present invention there is contemplated anapparatus, comprising: a magnetically responsive member having an ironbased soft magnetic alloy portion, the member having a bore formedtherein that is internally reinforced with a first high strengthmagnetic matrix composite zone for controlling bore growth, and whereinthe member is internally reinforced with a second high strength magneticmatrix composite zone substantially normal to the first high strengthmagnetic matrix composite zone, and further wherein the high strengthmagnetic matrix composite zones include the magnetic alloy and at leastone high strength fiber.

One object of the present invention is to provide a unique high speedmagnetic thrust disk.

Related objects and advantages of the present invention will be apparentfrom the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an aircraft having a gas turbine enginecoupled thereto.

FIG. 2 is an enlarged partially fragmented side elevational view of thegas turbine engine of FIG. 1.

FIG. 3 is an enlarged partial sectional view of one embodiment of thethrust bearing comprising a portion of the FIG. 2 gas turbine engine.

FIG. 4 is an enlarged sectional view of the selectively reinforcedmagnetic thrust disk comprising a portion of the FIG. 3 magnetic thrustbearing.

FIG. 5 is an enlarged partial sectional view of the thrust bearing ofFIG. 3, wherein a counteracting roll is shown in phantom lines.

FIG. 6 is a schematic cross sectional view of one embodiment of asandwich of magnetic alloy material and high strength reinforcing fibersprior to consolidation.

FIG. 7 is a schematic cross sectional view of an alternate embodiment ofa sandwich of magnetic alloy material and high strength fibers prior toconsolidation.

FIG. 8 is a schematic cross sectional view of one embodiment of asandwich of magnetic alloy and high strength reinforcing fibers afterconsolidation.

FIG. 9 is a schematic cross sectional view of one embodiment of anunconsolidated assembly comprising magnetic alloy material and highstrength fibers.

FIG. 10 is a schematic cross sectional view of another embodiment of anunconsolidated assembly comprising magnetic alloy material and highstrength fibers.

FIG. 11 is a plan view of a structure formed of the sandwich of themagnetic alloy and high strength reinforcing fibers of FIG. 8.

FIG. 12 is a cross-sectional view of an alternate embodiment of thereinforced magnetic thrust disk comprising a portion of the FIG. 3magnetic thrust bearing.

FIG. 13 is an exploded view of a portion of the reinforced thrust diskpreform components prior to consolidation.

FIG. 14 is an illustrative representation of the reinforced disk preformcomponents combined into a reinforced structure.

FIG. 15 is an illustrative view of one embodiment of the thrust diskhaving a pair of bonding rings engaging the disk during the bondingprocess.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiment illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended, such alterations and furthermodifications in the illustrated device, and such further applicationsof the principles of the invention as illustrated therein beingcontemplated as would normally occur to one skilled in the art to whichthe invention relates.

With reference to FIGS. 1 and 2, there is illustrated an aircraft 10having an aircraft flight propulsion engine 11. It is understood that anaircraft is generic and includes helicopters, tactical fighters,trainers, missiles and other related apparatuses. In one embodiment, theflight propulsion engine 11 defines a gas turbine engine integrating acompressor 12, a combustor 13 and a power turbine 14. Gas turbineengines are just one form of high-speed turbo machinery. In one form theturbine has a tip speed greater than 2,000 feet per second, and thecompressor has a rim speed greater than 1,400 feet per second. However,a person of ordinary skill in the art will appreciate that other tip andrim speeds are contemplated herein. The term “tip speed” is used hereinto denote the speed at the tip of the rotating airfoil, and the term“rim speed” is used herein to denote the speed at the rim of the rotordisk.

It is important to realize that there are a multitude of ways in whichthe components can be linked together. Additional compressors andturbines can be added with intercoolers connecting between thecompressors and reheat combustion chambers can be added between theturbines. Further, gas turbine engines are equally suited to be used forindustrial applications. Historically, there has been a widespreadapplication of industrial gas turbine engines such as pumping sets forgas and oil transmission lines, electricity generation, and navalpropulsion.

With reference to FIG. 2, there is illustrated an electromagnetic thrustbearing 15 having a thrust disk rotor 16 and a stator 17 for positioninga rotating element relative to a static structure. In one embodiment theelements are deployed within high-speed turbomachines, and in a morepreferred embodiment, the thrust disk rotor 16 has a rim speed greaterthan 800 feet per second. However, the present invention is applicableto thrust disk rotors operating at other speeds. Additionally, thethrust bearing 15 transmits to the static structure any axial loadapplied to or generated by the rotating elements. The thrust disk rotor16 is mounted on a shaft 18, which is rotatable within a mechanicalhousing of the gas turbine engine. It is understood that the bearingsystem set forth herein is equally applicable to a turbine and/or acompressor within the gas turbine engine.

The use of magnetic bearings instead of conventional oil lubricationbearings may facilitate the removal of the engine lubrication system,resulting in system weight reduction, reduced parasitic losses,simplification of the engine design and improved engine reliabilitythrough the elimination of bearing wear. Further, the use of magneticbearings instead of conventional oil lubrication bearings may benefitthe environment by eliminating the handling, storing and disposing ofsynthetic oils. While one aspect of the present invention relates to anelectromagnetic thrust bearing 15, it is important to realize that manyaspects of the present invention can be utilized with magnetic radialbearings, motors, generators, relays, and magnetic actuators. A pair ofcommonly owned U.S. patents, U.S. Pat. No. 5,658,125 entitled “MagneticBearings as Actuation for Active Compressor Stability Control”, and U.S.Pat. No. 5,749,700 entitled “High Speed High Temperature Hybrid MagneticThrust Bearing” are incorporated herein by reference.

With reference to FIG. 3, there is illustrated an enlarged view of theactive electromagnetic thrust bearing 15 wherein the magnetic thrustdisk rotor 16 is axially spaced from the stator 17. The components ofthe electromagnetic thrust bearing 15 are positioned relative to shaft18 so as to counteract axial thrust loading. The magnetic thrust disk 16in one preferred embodiment is a reinforced high-speed high temperaturedisk with a bore 20 formed therethrough. The magnetic thrust disk 16 isfixedly coupled to the rotatable shaft 18, and in a preferredembodiment, the bore 20 has a bore surface 20 a that is mated in aninterference fit with the outer surface 18 a of shaft 18. Stator 17 iscoupled to a portion of the gas turbine engine's static structure, whichincludes a mechanical housing 21. In a preferred embodiment, the thrustdisk rotor surface 22 and the stator surface 23 are substantiallyparallel and axially spaced from one another when the electromagneticthrust bearing has been actuated to produce forces to counteract theaxial trust loading.

The stator 17 has a structure comprising a magnetic alloy and one ormore coils 40 that when energized produce an attractive force betweenthe rotor 16 and the stator 17. More particularly, when theelectromagnetic thrust bearing 15 is actuated, a power supply (notillustrated) induces a current in the one or more coils 40, which emit amagnetic flux field, that intercepts the thrust disk 16. In oneembodiment, a control system 24 is utilized to adjust the current flowto the coils 40 so that the attractive force between the rotor 16 andthe stator 17 cancel the axial thrust load acting on the shaft.

Referring to FIG. 4, there is illustrated an enlarged partial sectionalview of the electromagnetic thrust disk 16 coupled to the rotatableshaft 18. The electromagnetic thrust disk 16 is a substantially annularmember that is press fit over the outside diameter of the shaft 18. Inthe preferred embodiment, the electromagnetic thrust disk 16 issymmetrical about an axial centerline X. The electromagnetic thrust disk16 preferably comprises an internally reinforced magnetically responsivemetallic material portion, and more preferably comprises an iron-cobaltmagnetic (Fe-Co) alloy. In one embodiment, cobalt is the primaryalloying element and the amount of cobalt by weight is less than about55%, and in a more preferred form, the amount of cobalt by weight is inthe range from about 20% to about 55%. These iron-cobalt alloys are highsaturation, high Curie temperature, low core loss soft magnetic alloysthat generally in an unreinforced state are not suited for therelatively high tensile capability needed for the rotational elementswithin gas turbine engines. However, iron-cobalt magneticallyresponsible alloys having other amounts of cobalt by weight arecontemplated herein.

A preferred embodiment of the thrust disk 16 comprises an internallyreinforced fabricated flat disk containing zones 25 and 26 that arereinforced with a high strength iron-cobalt metal matrix compositematerial. The reinforced zone 25 is disposed around the base/bore 20 andis designed and constructed to limit radial growth at the bore 20 andadd a high strength material system to this highly stressed region.Preferably, the reinforced zone 25 is radially short and extends alongthe bore 20. The minimization and/or elimination of radial growth of thebore 20 facilitates maintaining an interference fit between the thrustdisk 16 and the shaft 18. The reinforced radial zone 26 is spacedaxially from the rotor surface 22 of the thrust disk 16. Preferably, thereinforced radial zone 26 is radially long and axially thin. Thelocation, size, and number of reinforced zones are not intended hereinto be limited to what is disclosed in the specific embodiments set forthin the figures. The reinforcing zones have been shown as rectangular incross-section, however, other cross-sections are contemplated hereinincluding, but not limited to square, triangular, trapezoidal, and otherirregular cross-sections. Design parameters for a particular applicationmay dictate different zone configurations.

Referring to FIG. 5, there is illustrated one embodiment of thrust disk16 wherein the reinforced radial zone 26 is designed to induce acounterclockwise roll to the thrust disk 16 (the amount of roll isamplified in the drawing), which is indicated by dashed lines. Thecounterclockwise roll induced by the reinforced radial zone 26 cancelsat least a portion of the clockwise roll induced by the attractive forcebetween the rotor 16 and the stator 17. Balancing of the clockwise andcounterclockwise rolls positions the thrust disk rotor surface 22 andopposing stator surface 23 substantially parallel. Further, thebalancing of the roll in the thrust disk 16 allows a constant air gap 27to be maintained between the rotor surface 22 and the stator surface 23.In one embodiment, the radial reinforcing region 26 is disposed at thesubstantial axial midpoint between the thrust disk rotor surface 22 anda second surface 28 of the thrust disk 16. More particularly, it ispreferred that the rotor disk 16 has an asymmetrical geometry about aradial axis Y (FIG. 4) which is located at the axial midpoint betweensurface 22 and 28. Further, the rotor disk 16 is symmetrical about theaxial centerline X. The asymmetric geometry of the thrust disk 16 aboutthe radial axis Y induces an additional counterclockwise roll to thethrust disk 16 to counteract the clockwise roll induced by theattractive force between the rotor 16 and the stator 17. It isunderstood herein that the roll induced by the asymmetric geometry andthe roll induced by the radial reinforcing region 26 are balancedagainst the clockwise roll induced by the attractive forces between thestator 17 and the rotor 16 so as to position the rotor surface 22 andstator surface 23 substantially parallel and at a constant distanceapart.

The radial reinforcing zone 26 is a substantially planar annular diskthat is substantially parallel to the thrust disk rotor surface 22, andpositioned normal to the axial centerline X. Further, the radialreinforcing zone 26 is spaced radially from the reinforced zone 25. Inone embodiment the thrust disk 16 has a flux field portion 29 consistingsolely of the iron-cobalt magnetic alloy so as to provide optimumelectromagnetic properties within this portion.

With reference to FIGS. 6-10, there is illustrated schematicrepresentations of a composite material structure 35 utilizing a softmagnetic alloy 31 and a plurality of high strength fibers 30 to increasethe tensile strength of the structure 35 over the monolithic alloydefined by soft magnetic alloy 31. The composite structure may includethe prior described magnetic thrust disks along with, but not limitedto, other structures such as rotor laminates of an electric motor, orrotor laminates of a radial magnetic bearing. The composite structurehas specific utilization in an electromagnetic application, and moreparticularly has use in a group consisting of motors, generators, relaysand magnetic bearings. The present disclosure describes the compositesin terms of a high strength fiber, however, it is contemplated hereinthat a tungsten wire is useable as a reinforcing member in the metallicmatrix composites and structures defined herein. The composite structurewith a tungsten wire would be fabricated using the methods describedherein for the metallic matrix composites with fiber.

The soft magnetic alloy 31 preferably comprises a magneticallyresponsive metallic material and more preferably comprises an iron-basedsoft magnetic alloy, and most preferably comprises an iron-cobaltmagnetic (Fe-Co) alloy. In one embodiment, cobalt is the primaryalloying element and the amount of cobalt by weight is less than about55%, and in a more preferred form, the amount of cobalt by weight is inthe range from about 20% to about 55%. However, iron-cobalt magneticallyresponsive alloys having other amounts of cobalt are contemplatedherein. These iron-cobalt alloys are high saturation, high Curietemperature, low core loss soft magnetic alloys. In one form of thepresent invention, the composite structure 35 is defined by a fabricatedmetal matrix composite comprising at least one high strength fiber 30and the soft magnetic alloy material 31. In the preferred form of thefabricated composite structure 35, a plurality of high strength fibers30 and an iron-cobalt alloy define the metal matrix composite structure.More preferably, the high strength fibers 30 are continuous and orientedin a circumferential direction for increased hoop strength. Withreference to FIG. 4, there is illustrated an example of the use of thecomposite material structure within a thrust disk 16 which containsreinforced zones 25 and 26 that are formed of the composite structure35. While the embodiment of thrust disk 16 illustrated herein does notinclude high strength fibers oriented in a radial direction it iscontemplated herein that a composite structure can containcircumferential directed high strength fibers and/or radially directedhigh strength fibers. Further, chopped fibers can be utilized in analternate embodiment along with or in the place of continuous fibers.

Referring to FIG. 6, there is illustrated a schematic representation ofthe plurality of high strength fibers 30 positioned between layers ofthe magnetic metal matrix alloy in an unconsolidated state. In oneembodiment, the magnetic metal matrix alloy and the reinforcingmaterial/high strength fibers 30 are stacked in alternating layers withthe high strength fibers having a diameter of about 0.0056 inches, andthe layers of metal matrix alloy having a thickness in the range of0.003-0.015 inches. One preferred form utilizes metal matrix alloysheets having a thickness of about 0.012 inches. However, other fiberdiameters and metal matrix alloy thicknesses are contemplated herein.The unconsolidated assembly of magnetic alloy and the plurality of highstrength fibers are then subjected to manufacturing techniques such ashot isostatic pressing (HIP) or vacuum hot pressing (VHP). The abovemanufacturing techniques include a combined pressure and thermal cyclethat consolidate the magnetic metal matrix alloy 31 and the plurality ofhigh strength fibers 30, provide good bonding and improved mechanicalproperties. The bonding between the magnetic metal matrix alloy portiondefining a solid state joining. An illustration of the consolidatedcomposite structure is set forth in FIG. 8.

With reference to FIG. 7, there is illustrated an alternate embodimentof the unconsolidated assembly of magnetic metal matrix alloy layers 32and high strength fibers 30. The embodiment of FIG. 7 is substantiallysimilar to the embodiment of FIG. 6 with a difference being that thelayers of magnetic metal matrix alloy 32 have grooves 33 formed thereinto receive the plurality of high strength fibers 30 therein. In oneembodiment the grooves 33 are etched into the foil by conventionalphotolithographic techniques, however, other methods to form the groovesare contemplated herein. In one form of the present invention, thegroove depth and width is controlled to maintain fiber spacinguniformity and adequate consolidation. Upon being subjected to themanufacturing techniques such as hot isostatic pressing (HIP) or vacuumhot pressing (VHP), the layers of magnetic metal matrix alloy 32 andhigh strength fiber 30 are substantially consolidated as set forth inFIG. 8.

With reference to FIG. 9, there is illustrated a schematicrepresentation of an alternate embodiment of the unconsolidated assemblyof magnetic metal matrix alloy and high strength fibers. A structure isformed from a plurality of monotapes 37, which are stacked between amonolithic top member 38 a and a monolithic bottom member 38 b formed ofthe magnetic metal matrix alloy. A monotape 37 is formed by depositing amagnetic alloy powder around the high strength fibers and subsequentdrying. In one embodiment, the plurality of high strength fibers 30 havea diameter of about 0.0056 inches and the monotape has a thicknessindicated by “W” of about 0.0075 inches. However, other fiber diametersand monotape thicknesses are contemplated herein. The unconsolidatedassembly of monotapes 37 and members 38 a and 38 b are then subjected tomanufacturing techniques such as hot isostatic pressing (HIP) or vacuumhot pressing (VHP), which results in monotapes 37 and the members 38 aand 38 b being substantially consolidated as set forth in FIG. 8.

With reference to FIG. 10, there is illustrated another embodiment of anunconsolidated assembly 300 of magnetic metal matrix alloy, and highstrength fibers. A magnetic alloy wire 34 and the high strength fiber 30are arranged in an ordered fashion within a monolithic receiver 39A.When the receiver 39A is full a monolithic sheet of magnetic alloy 39Bis placed above the top of the receiver. In one embodiment the magneticalloy wire has a diameter of about 0.007 inches and the high strengthfiber has a diameter of about 0.0056 inches, however, other wire andfiber diameters are contemplated herein. The unconsolidated assembly 300is subjected to manufacturing techniques such as hot isostatic pressing(HIP) or vacuum hot pressing (VHP). Thus, the high strength fiber, themagnetic alloy wire, and the magnetic alloy receiver 39A and top member39B are substantially consolidated as set forth in FIG. 8. The assembly300 can be applied to axisymetric structures where the magnetic alloywire and the high strength fiber are co-wound on a mantrel and thensubsequently consolidated by hot isostatic pressing (HIP) or vacuum hotpressing (VHP).

The fiber reinforced magnetic metal matrix composite exhibit strengthsmuch higher than the monolithic magnetic alloy material. A person ofordinary skill in the art will appreciate that magnetic metal alloys arecommercially available; examples of commercially available alloysinclude, but are not limited to HIPERCO®-27, HIPERCO®-27HS, HIPERCO®50,and HIPERCO® 50 HS. The prior alloys are not intended to be limiting andalloys generally comprising about 20% to about 55% by weight cobalt andabout 45% to about 80% by weight iron with minor amounts of othermaterials such as Carbon, Manganese, Silicon, Nickel, Chromium,Vanadium, and/or Niobium are contemplated herein. Further, informationrelated to the material composition by weight percent is provided inTable 1. The data presented in Table 1 is typical or average values andis not intended to represent maximum or minimum values for thematerials.

In one embodiment, thin sheets of the magnetic metal matrix alloy arepositioned so as to sandwich layers of high strength fibers and thenprocessed under a combined high temperature and pressure cycle to obtaingood consolidation. Thin sheets of material can be sized to the desiredthickness by processes such as electro discharge machining (EDM) andetching. However, other techniques for sizing are believed within thecontemplation of someone of ordinary skill in the art.

TABLE I C Mn Si Ni Co Cr Fe V Nb HIPERCO ® 27 0.01% 0.25% 0.25% 0.60%27.0% 0.60% *Bal Na Na HIPERCO ® 27HS 0.23% 0.25% 0.25% 0.60% 27.0%0.60% *Bal Na Na HIPERCO ® 50 0.01% 0.05% 0.05% Na 48.75% Na *Bal 1.90%0.05% HIPERCO ® HS 0.01% 0.05% 0.05% Na 48.75% Na *Bal 1.90% 0.30%

The high strength fibers are preferably inorganic fibers, and morepreferably ceramic fibers. In one embodiment the fibers are desired as amonofilament fiber, and more preferably are formed of silicon carbide oralumina. However, multifilament fibers are also contemplated herein.Further, examples of some types of fibers that can be used, but are notintended to be limited herein, to enhance the tensile properties areavailable under the following tradenames: SCS-6™; Ultra SCS™; Sigma1240™; Sigma 1140™; Amercom™; Trimarc™ 1 Trimarc™ 2, and, Saphikon™,which is a single crystal alumina fiber. The fibers are believedgenerally known to one of ordinary skill in the art. Further, the Sigma1240™ and Sigma 1140™ fibers have a tungsten core (W) with aTitanium-Boron (TiB₂) coating. The SCS-6™ fiber is manufactured byTextron Specialty Materials and has a carbon core with a columnar layerof silicon carbide deposited in two passes. Ultra SCS™ fiber ismanufactured by Textron Specialty Materials and has a carbon core with asingle pass layer of equiaxed silicon carbide deposited by chemicalvapor deposition techniques. The Trimarc™ I fiber has a tungsten corewith a silicon carbide coating. Trimarc™ 2 fiber has a carbon core witha silicon carbide coating. Saphikon™ is a fiber defined by a singlecrystal AL203,EFG process. Further, the high strength fibers may becoated with the magnetic alloy or refractory elements prior toconsolidation so as to minimize interfacial reactions duringconsolidation. A chemical vapor deposition (CVD) or a physical vapordeposition (PVD) process can be utilized to coat the high strengthfibers. In one embodiment the Amercom™ fibers are coated with tungsten(W). This tungsten coating forms a good bond with the Amercom™ fibersand also serves as a reaction barrier between the fibers and the ironcobalt matrix alloy.

One preferred composite structure utilizes HIPERCO™-27 as the magneticalloy material and a plurality of continuous high strength fibers soldunder the trademark Ultra SCS. In one embodiment, the compositestructure is fabricated by subjecting the unconsolidated assembly to ahot isostatic pressing operation (HIP), or vacuum hot pressing (VHP)operation at temperatures within the range of about 1350° Fahrenheit toabout 1800° Fahrenheit and under pressures between about 10 Kpsi toabout 30 Kpsi (Kpsi—one thousand pounds/square inch) and hold times atthe maximum temperature between two and six hours. It is understood thathot isostatic pressing (HIP) and vacuum hot pressing (VHP) are wellknown to people of ordinary skill in the art.

The quantity, size and spacing of the fibers 30 as shown herein, isillustrative and is not intended to be read as a limitation. While thefigures illustrate a plurality of high strength fibers, a compositestructure having a single high strength fiber is contemplated herein. Inthe preferred embodiment, the plurality of circumferentially extendingfibers 30 are spaced from one another in either an axial direction or ina radial direction. The present invention is applicable in bothsingle-ply and multi-ply structures. In the preferred embodiment, thereinforced zones have a fiber cross-sectional area that is within therange of about 30-40% of the cross-section of the reinforced zones.After processing by hot isostatic pressing (HIP) or vacuum hot pressing(VHP), the plurality of high strength fibers 30 are bound together bythe magnetic metal matrix alloy 31. Further, the magnetic metal matrixalloy 31 forms an exterior covering to protect the plurality of fibers30 from damage due to handling or environmental effects. In oneembodiment, the reinforced areas near the edges of the thrust diskmaintain an exterior covering thickness within a range of about 0.030inches to about 0.080 inches. However, other exterior covering thicknessare within the scope of the present invention.

Referring to FIG. 11, there is illustrated a plan view of acircumstantial structure 200 formed of metal matrix alloy 31 and acontinuous circumferential high strength fiber 30. In one form, the highstrength fiber is a continuous circumferential winding extending fromthe ID to the OD of the reinforced zone. The structure 200 has beenfully consolidated and the metal matrix alloy 31 encapsulates the fiber30 and the fiber 30 increases the tensile capability of the structure.

With reference to FIG. 12, there is illustrated an alternativeembodiment of a magnetic thrust disk 100 capable of operating at thehigh rotational speeds associated with a gas turbine engine. Themagnetic thrust disk 100 defines a composite structure having aplurality of circumferential oriented high strength fibers 30 heldtogether by the magnetic metal matrix 31 to form a composite reinforceddisk. While the embodiment of thrust disk 100 has a substantiallyhomogenous distribution of reinforcing fibers 30 in the cross-section,it is understood that in an alternate embodiment the distribution is nothomogenous and there are regions without localized high strength fiberreinforcement.

With reference to FIGS. 13-15, there is illustrated a method formanufacturing a ring and/or disk containing select regions reinforcedwith a metallic matrix composite material. Metallic matrix compositesare defined herein to include metal matrix composites and intermetallicmatrix composites, and is not intended to be limited to use with metalmatrix composites utilizing magnetic alloys. The method of manufacturewill be described with reference to the production of a thrust disk,such as a disk 16. However, it is understood herein that other thrustdisks having other geometries and regions of reinforcement are withinthe scope of present method of the manufacture. While an annular disk isillustrated, it is understood that a solid disk can be produced with themethods of the present invention. The method of manufacture isapplicable to all forms of metallic matrix composites. While the methodof manufacture will be described regarding introducing metallic matrixcomposite reinforcements of uniaxial hoop orienting fibers into selectregions of a disk, it is understood that the method of manufacture wouldapply to other fiber orientations or combination of fiber orientationswithin a single zone or plurality of zones within the structure.

The selectively reinforced thrust disk is produced by combining a numberof individual components. Referring to FIGS. 13-15, there is illustrateda preferred form of the present invention in which the components aresymmetrical about the centerline X and define an annular disk. However,the present invention is applicable to other configurations, which arenot symmetrical about the centerline. In one embodiment the individualcomponents include a metallic c-section cup 51, a metallic cap 52, apair of metallic rings 53, a radial reinforcing zone 54 and a borereinforcing zone 55. In a more preferred embodiment the metalliccomponents 51, 52 and 53 are monolithic, however, the disclosure is notintended to be limited herein to monolithic components. Further, thegeometry is not limited to an annular c-section cup, and other geometricconfigurations for members having a space herein is contemplated by thepresent invention. As disclosed above, the reinforcing zones comprisemetallic matrix composite material formed from any one of the commonfiber matrix lay up procedures, including, but not limited to;foil-fiber-foil, coated fiber, tape casting or wire-fiber. It ispreferred that the reinforcing zones comprise magnetic metal matrixcomponents; however, the present method is not limited to use withmagnetic metal matrix components.

In a preferred form of the present invention, the metallic matrixcomposite reinforcing zones 54 and 55 are in an unconsolidated form whenmade a portion of a perform assembly 80. The entire preform assembly 80is then subjected to a pressure and thermal cycle associated with hotisostatic pressing (HIP) or vacuum hot pressing (VHP). Subjecting thepreform assembly 80 with unconsolidated reinforcing zones to a singleconsolidation process maximizes the composite materials strength by onlysubjecting the plurality of high strength fibers within the reinforcingzones to a single temperature cycle. In an alternate embodiment, themetallic matrix composite reinforcing zones are formed ofpre-consolidated components, which have undergone a first thermal andpressure cycle. In the alternate embodiment the preform assembly 80includes the pre-consolidated composite zones and the entire preformassembly is then subjected to a temperature and pressure cycle in orderto bond the components together. The pressure and thermal cycle causesthe metallic matrix to be metallurgically bonded to the metallic membersforming a portion of the preform assembly 80.

The composite bore-reinforcing zone 55 is placed within the c-sectionshaped space 56 of the monolithic c-section cup 51. The composite borereinforcing zone 55 is of an annular section and has an inner surface100 disposed adjacent the c-section cup 51. Thereafter, one of the rings53 is placed within the space 56 adjacent the bore reinforcing zone 55in the c-section cup 51. The radial reinforcing zone 54 is positionedadjacent and abutting the first ring 53 and the second ring 53 isdisposed adjacent and abutting the radial reinforcing zone 54 within thespace 56. The cap 52 is positioned adjacent the open end 81 of thec-section cup 51.

In one embodiment, the environment within the space 56 is evacuated andthe c-section cup 51 and the cap 52 are welded together in order toprovide a sealed environment. The welding operation is preferably doneby electron beam welding. In an alternate embodiment, which is oftenutilized for materials that cannot be easily welded together, thepreform assembly is evacuated and encased in a steel bag, which is thensealed by welding. After the preform assembly 80 has been properlyevacuated and placed in a sealed state, the assembly 80 is subjected toa hot isostatic pressing (HIP) operation to consolidate the metallicmatrix reinforcing zones and join the plurality of monolithic componentstogether and join a portion of the metallic matrix to the components. Inthe case where the reinforcing zones were pre-consolidated the secondthermal and pressure cycle results in the bonding of the individualcomponents together. In one embodiment, the assembly 80 is consolidatedat temperatures within a range of about 1350° Fahrenheit to about 1800°Fahrenheit and under pressures between about 10 kpsi to about 30 kpsiand hold times at the maximum temperature between about two and aboutsix hours.

The preferred form of the method of manufacturing includes placing thepreform assembly 80 on a thick member 101 to back up the assembly andminimize distortion during the high temperature and pressure cycle. Inthe preferred form of the present invention the thick member 101 definesa molybdenum plate, and more preferably is a molybdenum plate having athickness of about 0.5 inches. Further, a restraining ring 102 may bepositioned around the outer periphery of the outer wall member of thepreform assembly to aid in the generation of pressure at the bondinginterfaces during the joining process. Preferably, the restraining ring102 is formed of a molybdenum material. An inner member 103 can beplaced within the bore of the preassembly 80 to abut an outer surface104 of the metallic member 51 to generate bond interface pressure duringthe joining process. In a preferred form of the present invention theinner member 103 defines a molybdenum ring. The preform assembly 80after being subjected to the bonding cycle is machined as needed to thedesired geometry by known manufacturing techniques.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly the preferred embodiment has been shown and described and that allchanges and modifications that come within the spirit of the inventionare desired to be protected.

What is claimed is:
 1. An electromagnetic thrust bearing, comprising: astator having a stator surface; a rotor having a rotor surface spacedfrom said stator surface, said rotor having a first internallyreinforced portion for inducing a first roll to said rotor to cancel atleast a portion of an opposite second roll induced in said rotor by anattractive force between said rotor and said stator.
 2. The thrustbearing of claim 1, which further includes an axial centerline, andwherein said first internally reinforced portion extending radiallyrelative to said axial centerline.
 3. The thrust bearing of claim 2,wherein said first internally reinforced portion is proportioned suchthat it is radially long and axially short.
 4. The thrust bearing ofclaim 3, wherein said rotor has a rotor portion formed of a softmagnetic alloy and wherein said first internally reinforced portion isformed of at least one elongated high strength member bonded with aquantity of a soft magnetic alloy.
 5. The thrust bearing of claim 4,wherein said at least one high strength member defines a plurality ofelongated high strength members which are continuous and extendcircumferentially within said rotor, and wherein an exterior skin formedof said magnetic alloy covers said rotor.
 6. The thrust bearing of claim5, wherein said soft magnetic alloy comprises an iron-cobalt material,and wherein said plurality of high strength elongated members are formedof an inorganic material.
 7. The thrust bearing of claim 6, wherein eachof said high strength members define a high strength fiber formed of amaterial selected from the group consisting of SCS-6™, Ultra SCS™, Sigma1240™, Amercom™, Saphikon™, Sigma 1140™, Trimarc 1™, and Trimarc 2™, andwherein said magnetic alloy has from about twenty percent to aboutfifty-five percent by weight cobalt.
 8. The thrust bearing of claim 5,wherein at least one of said high strength members is formed of atungsten wire.
 9. The thrust bearing of claim 1, wherein said first rollis a counterclockwise directed roll for counteracting said secondclockwise roll associated with the attractive forces between said rotorand said stator, and wherein said rotor has a radial axis that extendsradially from an axial midpoint of said rotor, and wherein said rotor isasymmetric about said radial axis and said rotor asymmetry induces athird roll in a counterclockwise direction for counteracting theattractive forces between said rotor and said stator.
 10. The thrustbearing of claim 1, wherein said rotor has a bore, and which furtherincludes a second internally reinforced portion adjacent said bore tocontrol bore growth.
 11. The thrust bearing of claim 1, which: furtherincludes a shaft rotatable within a gas turbine engine; said rotor isfixedly coupled to said shaft and spaced from said stator so that theattractive forces between said rotor and said stator counteract axialthrust loading, and wherein said rotor defines a magnetic thrust diskhaving a substantially annular configuration with a bore disposed in aninterference fit with said shaft; a second internally reinforced portionformed of a plurality of high strength elongated members that arecontinuous and extend circunferentially and a soft magnetic alloy todefine a consolidated metal matrix composite, and wherein said secondinternally reinforced portion minimizing the growth of said bore; andsaid first internally reinforced portion is formed of a plurality ofhigh strength elongated members that are continuous and extendcircumferentially and a soft magnetic alloy to define a consolidatedmetal matrix composite, and wherein a remainder portion of said rotordisk is formed of said soft magnetic alloy.
 12. The thrust bearing ofclaim 11, wherein said reinforced portions are substantiallyencapsulated by said soft magnetic alloy, and wherein said soft magneticalloy is defined by an iron-cobalt type material comprising from abouttwenty percent to about fifty-five percent by weight cobalt and fromabout forty-five percent to about eighty percent by weight iron, andwherein said plurality of high strength elongated members are selectedfrom one of a high strength fiber and a high strength wire.
 13. Thethrust bearing of claim 12, wherein said plurality of high strengthelongated member include a tungsten wire.
 14. An apparatus, comprising:a magnetically responsive member having an iron based soft magneticalloy portion, said member having a bore formed therein that isinternally reinforced with a first high strength magnetic matrixcomposite zone for controlling bore growth, and wherein said member isinternally reinforced with a second high strength magnetic matrixcomposite zone substantially normal to said first high strength magneticmatrix composite zone, and further wherein said high strength magneticmatrix composite zones include said magnetic alloy and at least one highstrength fiber.
 15. The apparatus of claim 14, wherein said member has atensile strength greater than the tensile strength of said iron basedsoft magnetic alloy portion, and wherein said at least one high strengthfiber is joined with said magnetic alloy.
 16. The apparatus of claim 14,wherein said at least one high strength fiber defines a plurality ofhigh strength fibers, and wherein each of said plurality of highstrength fibers are bound together by said magnetic alloy.
 17. Theapparatus of claim 14: which further includes an active electromagneticstator for emitting a magnetic flux field that interacts with saidmember; said member has a circular shape and a tensile capacity greaterthan the tensile capacity of said soft magnetic alloy portion; said atleast one high strength fiber defines a plurality of high strengthfibers oriented in a substantially circumferential direction; andwherein each of said magnetic matrix composite zones are consolidatedand said plurality of high strength fibers are bound together by saidmagnetic alloy.
 18. The apparatus of claim 17, wherein said magneticalloy material defines an iron-cobalt type material having less thanabout fifty-five percent by weight cobalt and about forty-five percentto about eighty percent by weight iron, and wherein said plurality offibers are inorganic monofilaments.
 19. The apparatus of claim 14: whichfurther includes a gas turbine engine having a shaft; and said bore andsaid shaft are maintained in interference fit during normal operation ofsaid engine.
 20. The apparatus of claim 14, wherein said member has atensile strength greater than the tensile strength of said iron basedsoft magnetic alloy portion, and wherein at least one of said highstrength magnetic matrix composite zones has a high strength wiretherein.
 21. The apparatus of claim 20, which further includes at leastone high strength fiber within said at least one of said high strengthmagnetic matrix composite zones.
 22. The apparatus of claim 21, whereinsaid high strength wire is defined by a tungsten wire.